This patent application claims priority based on a Japanese patent application, 2000-5241 filed on Jan. 5, 2000 the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a member used for a charged beam processing apparatus such as an electron beam exposure apparatus. More particularly, the present invention relates to a member such as a mask that can prevent electrification caused by the charged beam.
2. Description of the Related Art
A mask having a plurality of blocks, on which a predetermined pattern is formed, is provided to the electron beam exposure apparatus that uses a block exposure method. During the exposure process of the electron beam exposure apparatus, the mask is irradiated by the electron beam. If the mask is charged up by the electron beam, the accuracy of the position of the pattern, which is to be exposed to the wafer, deteriorates. Therefore, for example, as disclosed in Japanese Patent Application Laid-Open No. H7-326556, the attempt is made to form a metal film made from gold, for example, on the mask surface, to prevent the mask from being charged up.
During irradiation of the electron beam in the electron beam exposure apparatus, a contaminated organic membrane is generated on the mask by carbon, for example. This contaminated organic membrane is thought to be generated by the carbon (C) existing in the vacuum attached to the substrate such as the mask. To prevent the generation of this contaminated organic membrane, performing the exposure process including performing an O2 plasma cleaning or O3 (ozone) cleaning, is effective.
However, because the oxidizing effect of the ozone gas and O2 plasma gas is strong, the gold film formed for preventing the charge up, is oxidized. The oxidized gold film will be a cause of the electrification that deteriorates the accuracy of the position of the pattern, which is to be exposed to the wafer. Therefore, it is important not to oxidize the member, such as the mask, in the oxidizing atmosphere where the oxidizing reaction easily occurs, in order to form a high accuracy pattern on the wafer.
Therefore, it is an object of the present invention to provide a member such as a mask, which overcomes the above issues in the related art. This object is achieved by combinations described in the independent claims. The dependent claims define further advantageous and exemplary combinations of the present invention.
According to the first aspect of the present invention, a member adopted to be irradiated by a charged beam in an oxidizing atmosphere in a charged beam processing apparatus; can be provided such that the member comprises: a region, which is to be irradiated by the charged beam, which is covered by a conductive and not oxidizable material or a material that becomes a conductive oxide when the material is oxidized.
Furthermore, one material may be a carbide, boride, or nitride of a metal having a high melting point. The material may be a conductive ceramic material. The material may be a conductive oxide.
According to the second aspect of the present invention, a mask, on which a predetermined pattern is formed, adopted for a use in an electron beam exposure apparatus can be provided such that the mask comprises: a substrate, on which the predetermined pattern is formed by a material through which an electron beam does not pass; and an antioxidant layer, which is formed on a surface of the substrate by a conductive and not oxidizable material or a material that becomes a conductive oxide when the material is oxidized.
The surface may be a region, which is to be irradiated by the charged beam, of the substrate. The surface may be both upper and back faces of the surface of the substrate. The surface may be a whole surface of the substrate. The material that forms the antioxidant layer may be a carbide, boride, or nitride of a metal having a high melting point. The material that forms the antioxidant layer may be a conductive ceramic material. The material that forms the antioxidant layer may be a conductive oxide.
According to the third aspect of the present invention, an electron beam exposure apparatus which exposes a wafer in an oxidizing atmosphere to an electron beam can be provided such that the apparatus comprises: an electron gun that generates an electron beam; a plurality of members for irradiating the electron beam on a predetermined region of the wafer; and a wafer stage, on which the wafer is installed; wherein: at least a part of a region of a member, which is to be irradiated by the electron beam from among the plurality of members, is covered by a conductive and not oxidizable material or a material that becomes a conductive oxide when the material is oxidized.
According to the fourth aspect of the present invention, a method for manufacturing a semiconductor device on a wafer can be provided such that the method comprises: generating an electron beam; deflecting the electron beam to a predetermined region of a mask, a surface of which is covered by a conductive and not oxidizable material or a material that becomes a conductive oxide when the material is oxidized, in an oxidizing atmosphere; deflecting the electron beam, which passed through the mask, to a predetermined region of the wafer; and exposing the predetermined region of the wafer using the electron beam.
According to the fifth aspect of the present invention, a method for manufacturing a mask for an electron beam exposure apparatus can be provided such that the method comprises: preparing a substrate having two silicon layers that sandwich a silicon oxide film; forming a predetermined pattern on both sides of the silicon layers; and covering a surface of the substrate with a conductive and not oxidizable material or a material that becomes a conductive oxide when the material is oxidized.
The covering may cover a region, which is to be irradiated by the charged beam, of the surface of the substrate with the material. The covering may cover both upper and back faces of the surface of the substrate with the material. The covering may cover a whole surface of the substrate with the material. The covering may cover the surface of the substrate with a carbide, boride, or nitride of a metal having a high melting point. The covering may cover the surface of the substrate with a conductive ceramic material. The covering may cover the surface of the substrate with a conductive oxide.
This summary of the invention does not necessarily describe all necessary features of the present invention. The present invention may also be a sub-combination of the above described features. The above and other features and advantages of the present invention will become more apparent from the following description of embodiments taken in conjunction with the accompanying drawings.